In retrieving stored videos, it is known to selectively obtain a desired video based on secondary information such as the title of the video, its creation date, the creator of the video and the amount of data in the video, by using character strings which are added to the videos. A desired video may be reached by using a fast-forward or rewind operation until a specific part is reached. However, when the number of videos that are stored is large in both number and quantity of data, this retrieval method is disadvantageous in that it requires a substantial amount of time to search for a desired video.
An example of a technique used for retrieval in a motion picture database is disclosed in Japanese Patent Publication No. HEI 6-101018 (1994). According to this example, a frame of a moving picture is divided into blocks on the basis of the motion of objects in the motion picture data. A specific object is retrieved from the motion picture data by using the calculated motion data as a retrieval index. However, still pictures included in the motion pictures are not used as a retrieval index.